Ads on Facebook, Yahoo, etc.=virus?

[Mac]

I've been getting ads on sites like Facebook, Yahoo!, etc, that are normally seen on "less secure" sites. They're they ads that tell you to click, or are a game, or try to look like a facebook notification. Under the ad, it always says "ads not by this site"
I've never noticed these type of ads before, and was wondering this could be some type of ad-ware, spy-ware or a virus.

*As I'm typing this, I have two ads, one above and one below the area where I'm typing. It have three Giraffes and tells you to click the tallest one.
thanks.

[Casca Longinus]

Install, and run full scans with these two programs, they are free:

http://download.cnet.com/Malwarebytes-An...04572.html
Decline the free trial on install to keep the free version.

http://www.superantispyware.com/

Then google ad blocking, and pop up blocking add-ons for your browser.

[DunbarPappy®ϟϟ]

Although those specific ads may be harmless, there can never be certainty about assets that are being gathered and displayed by the browser. This is done automatically unless users constrain it.
And because ads are so fluid, malware can be included well before they are discovered and taken down.
(Read this eye opener: https://www.pcworld.com/businesscenter/a...y_day.html

You must modify your browsers 'automatic' behavior so it restricts what gets returned, for both security and privacy.

Get Firefox as your default browser & use it for everyday tasks.
The following mods help, but methods ("vectors") are dynamic, and users must stay abreast of daily threats.
FIREFOX: Tools> Options> Privacy> top drop menu set to "Firefox will use custom settings..."> Check 'Accept Cookies from sites'
â–ºUn-Check 'Accept 3rd Party cookies'.
And tick the very top box regarding "Do Not Track".

A good collection of effective add-on's (Official Mozilla) is here:
https://addons.mozilla.org/collections/d...nbarpappy/
AdBlock Plus (with 'subscription' added) & "Better Privacy" also helps defray rubbish.
►► At minimum, get the #1 item for malware prevention: "NoScript", which constrains automagically fetching & deployment of potentially tainted assets.
[Bookmark and refer to this page for how it works, and how to use it...very straight forward; http://noscript.net/features#contentblocking

[Note that ticking the X to close the ad window may in fact install the malware if so configured: the real action the X does could be hidden in the unseen "iFrame", and 'closing' the window is a not safe tactic.]